JP3214972B2 - Fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device such as a copying machine or a printer for fixing an unfixed image such as a toner image on a recording material such as paper by a heating roller or a fixing film and a pressure roller. The present invention relates to a technique for controlling a core metal potential of a semiconductor device.

[0002]

2. Description of the Related Art In a fixing device used in an image forming apparatus such as a copying machine or a printer, a pressure roller having a heating roller heated by a heat source such as a halogen heater and an elastic layer as a surface layer pressed against the heating roller. A so-called heat fixing method in which a roller constitutes a conveying means of a recording material such as paper, and an unfixed toner image is fixed on the recording material by both rollers is a mainstream. In this heat fixing method, a technique for controlling the core metal potential of the heating roller and the pressure roller has been started to be used for the purpose of improving fixing performance or safety.

FIG. 8 shows an example of such a conventional core metal potential control technique in which the core metal potential of a pressure roller is controlled. In FIG. 8, 1 is a heating roller, and 6 is a pressure roller. The pressure roller 6 is provided with a fixed shaft 7 fixed in the rotational direction as a central shaft, and the fixed shaft 7 uses an outer ring driven ball bearing 9 as a bearing member. 9 supports the metal core 6-a. A conduction ring 18 is sandwiched between the thrust between the cored bar 6-a and the ball bearing 9, and the conduction ring 18 rotates together with the pressure roller 6. Conductive ring 1 rotating in this way
8 on the fixed side, the contact 19- of the conduction spring 19
a is urged to provide a sliding contact. The sliding contact is provided while the conductive ring 18 is rotated to make contact with the conductive ring 18 to establish conduction. Then, by grounding the contact 19-a via the diode 8, the potential of the metal core 6-a of the pressure roller is controlled to a predetermined potential.

[0004] As a method of controlling the core potential of the pressure roller, an example shown in FIG. 9 has also been proposed. In this case, the pressure roller 6 has a shaft-shaped core 6-a, and is supported by the slide bearing 20 and rotates. Contact 19 of conduction spring 19
-A is the outer periphery of the slide bearing 20 and the core 6 of the pressure roller.
-A, and conduction is achieved by the sliding contact. The point that the contact 19-a is grounded via the diode 8 is the same as in the above example.

[0005]

However, the conventional example described with reference to FIG. 8 has the following disadvantages.

[0006] (1) both of the conduction ring 18 and the pressure roller 6
Since the conduction of the members is caused by the contact in the thrust direction , the contact pressure is not stable because there is a relative movement between the two members due to the play in the thrust direction in terms of structure. (2) Contact 19-a between conduction ring 18 and conduction spring 19
Not only is not stable for the same reason, but also the wear of the sliding contact 19-a and the variation in the contact pressure are large, and the contact pressure fluctuates, so that noise is likely to occur. (3) The conduction ring 18 is connected to the pressure spring 1 together with the pressure roller 6.
Since the position is changed by the force of No. 3, the contact point of the conductive spring 19 with the contact 19-a is not stable. (4) The sliding portion of the heating roller 1 with respect to the bearing 3 is an aluminum metal surface, and since the distance between the sliding ring 18 and the conductive ring 18 is short due to the structure, leakage is easy. In other words, this is a great constraint on the controllable core potential.

In the conventional example described with reference to FIG.
Although the above-mentioned drawbacks are small in the thrust direction, the core metal 6-a of the pressure roller 6 and the contact 19-
In this case , the contact pressure with the pressure roller 6
However, there is a drawback that it is not stable because it relatively moves.

Further, the above-mentioned conventional example is a fixing device of a system using a heating roller.
No. 82, JP-A-2-1577878, JP-A-4
As disclosed in JP-A-44075-44083 and the like, a heat source is provided on one side of a heat-resistant film, and a recording material is brought into close contact with the other side to travel and move the recording material together with the film so that the heat energy of the heat source is transferred to the film. There has also been proposed a fixing device of a type in which the toner is applied to a recording material and a toner image on the recording material via the recording medium, and this fixing device also has the same disadvantages as described above regarding the control of the core metal potential of the pressure roller.

In the above-described conventional example, the potential is controlled only for the core of the pressure roller. However, there is also a conventional apparatus for controlling the potential of the core of the heating roller together with the pressure roller. There were similar drawbacks.

Therefore, the present invention solves the above problems,
It is an object to provide a fixing device as described below.

First, the first invention according to the present application can realize a reliable potential control by stabilizing the contact pressure of the sliding contact, and does not generate noise at the contact. It is intended to provide a fixing device.

Next, the second invention according to the present application, in addition to the above objects, improves the stability of the contact pressure of the sliding contact with respect to the movement of the roller in the thrust direction and the radial direction, in particular,
It is still another object of the present invention to provide a fixing device capable of preventing leakage with a conductive member provided outside the roller.

A third invention according to the present application is intended to improve the stability of contact pressure against abrasion of sliding contacts in addition to the objects to be solved by the first and second inventions. It is an object of the present invention to provide a fixing device that can perform the fixing.

Further, the fourth invention according to the present application provides the contact pressure of the sliding contact in a system using a film and a roller, in addition to the objects to be solved by the first to third inventions. It is an object of the present invention to provide a fixing device capable of improving the stability of the fixing device.

[0015] The fifth invention according to the present application provides, in addition to the object to be solved by the first to third inventions, a system using a heating roller and a pressure roller.
It is an object of the present invention to provide a fixing device capable of improving the stability of the contact pressure of a sliding contact.

Further, the sixth invention according to the present application improves the stability of the sliding contact even when controlling the potential of the core metal of the heating roller in addition to the object to be solved by the fifth invention. It is an object of the present invention to provide a fixing device that can perform the fixing.

[0017]

According to a first aspect of the present application Means for Solving the Problems] The object is you nipped and conveyed the recording material bearing an unfixed image recording material conveying member pair with this recording material conveying member pairs and a heat source disposed on at least one of the, in the fixing device you fixing an unfixed image on a recording material, the recording material conveying member
And the central axis at least one pair, the bearings on the central shaft
Ri is rotatably supported, and a roller body having a core metal and provided on the core metal, et al were coated <br/> layer, conduction between the metal core and the central axis
Sliding member provided on the center side of the bearing
This is achieved by having a conducting member conducting the central axis on the outside .

Further, according to the second invention of the present application,
The above object is achieved in the first aspect of the present invention by forming the core of the roller body into a cylindrical shape and providing sliding contacts on the inner peripheral surface side of the core.

Further, according to a third aspect of the present invention, the above object is achieved in the first aspect, wherein the core of the roller body has a cylindrical shape, and the sliding contact is provided on the outer peripheral surface side of the central axis. This is achieved by:

According to the fourth aspect of the present invention,
The object is, in the first to third inventions, a recording material transporting body pair , one of which is a roller body, the other is a film-shaped member arranged endlessly movable, the roller body, A heat source disposed inside the film-like member,
This is achieved by arranging them so as to be pressed against each other via the film-shaped member.

Further, according to a fifth aspect of the present invention, the above object is achieved in the above first to third aspects by providing a recording material conveying member pair , one of which has a heating roller having a heat source therein. The other is achieved by using a pressure roller provided so as to be in pressure contact with the heating roller, and using a roller body provided with sliding contacts as the pressure roller.

According to a sixth aspect of the present invention,
The object of the present invention is to provide the recording material transporting body pair according to the first to third aspects, wherein one of the pair of recording material conveying members is a heating roller having a heat source therein, and the other is a pressing member disposed so as to press against the heating roller. This is achieved by forming the rollers as rollers, and forming both rollers as roller bodies provided with sliding contacts.

[0023]

According to the first aspect of the present invention, the core for the roller body is rotated around the central axis via the bearing member, thereby providing a contact for providing a sliding contact. Is secured in the gap between the mandrel and the central shaft, and the sliding contact is further axially centered than the bearing member , i.e.,
The contact area is stable because the sliding contact does not move even if the center axis or the core is displaced.
Secured as Te surface, stable allowed to contact pressure. As a result, reliable core metal potential control is performed, and no noise is generated at the contacts.

According to the second aspect of the present invention,
Since the core of the roller body has a cylindrical shape and the sliding contact is provided on the inner peripheral surface side of the core, even if the center axis or the core is displaced in the thrust direction, the contact area of the sliding contact is the core. Secured on the inner peripheral surface of the gold cylinder, a stable contact pressure can be obtained. Further, even if the center axis is displaced in the radial direction, there is no relative displacement of the core, so that the sliding contacts provided on the inner peripheral surface of the core do not displace, and a stable contact pressure can be obtained. Further, the position of the sliding contact is secured at a sufficient distance from the conductive member outside the roller body, so that no leakage occurs.

According to the third aspect of the present invention,
Since the core of the roller body has a cylindrical shape and the sliding contact is provided on the outer peripheral surface side of the central shaft, not only does the same effect as in the second invention, but also the outer peripheral surface of the central shaft has the inner peripheral surface of the core. Since the diameter is smaller than the surface, the sliding speed is reduced, and the wear resistance is improved.

Further, according to the fourth aspect of the present invention, even if one of the pair of recording material conveyance members is a film-shaped member which is disposed to be endlessly movable, the sliding contact is in the above-mentioned position. As described above, the roller body is conventionally disposed such that the roller body is pressed into contact with a heat source disposed inside the film-shaped member through the film-shaped member, and in a film-type fixing device, Realizes reliable core metal potential control by stabilizing the contact pressure of the contact.

Further, according to the fifth aspect of the present invention, by providing the sliding contacts on both the heating roller and the pressure roller, more reliable core metal potential control can be realized.

[0028]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2 are cross-sectional views showing one embodiment of the fixing device of the present invention. As shown in FIGS. 1 and 2, this embodiment is an example in which a heating roller 1 and a pressure roller 6 are used as a pair of recording material conveying members. In the same drawing, a heating roller heated by a halogen heater 2 as a heat source is used. 1 is attached to a frame 4 via a bearing 3. The heating roller 1 is driven by a gear 5. On the other hand, a pressure roller 6 which is in pressure contact with the heating roller 1 is a cylindrical cored metal 6-a.
And an elastic rubber layer 6-b and a surface layer 6-c as covering layers on the surface. Here, the core metal 6 of the pressure roller 6
-A is supported via a ball bearing 9 as a bearing member with respect to a fixed shaft 7 fixed in the rotation direction as a central axis. That is, the pressure roller 6 rotates with the rotation of the outer ring of the ball bearing 9.

The fixed shaft 7 comprises an insulator 11, a pressure plate 12
Is pressed by the pressure spring 13 and pressed against the heating roller 1.

Further, the pressure conducting plate 10 is attached to the fixed shaft 7 inside the ball bearing 9 and the pressure conducting plate 1
A contact 10-a as a sliding member is attached to the leading end of 0, and this contact 10-a contacts the metal core 6-a of the pressure roller 6 to form a sliding contact.

Therefore, the metal core 6-a of the pressure roller 6 has the same potential as the fixed shaft 7 via the pressure conduction plate 10. Further, the fixed shaft 7 is contacted by a leaf spring (not shown), and
Through a diode 8 serving as a ground.

Details of mounting the pressure conducting plate 10 will be described with reference to FIG. FIG. 3 is a sectional view taken along line AA in FIG. Arrows in the drawing indicate the rotation directions of both rollers.
The pressure conducting plate 10 is positioned and fixed by the fixed shaft 7. The pressure conducting plate 10 is made of a leaf spring material, and a contact pressure is obtained by bending the arm portion 10-b.
Here, the concentricity of the core metal 6-a of the pressure roller 6 and the fixed shaft 7 is maintained by the ball bearing 9.
The deflection of 0-b is also kept constant, and the contact pressure of the sliding contact by the contact 10-a is also stabilized. As a result, reliable core metal potential control becomes possible, and no sound change is generated at the contact point. In addition, since the distance between the sliding contact and the heating roller 1 is sufficiently large, no leak occurs.

Next, details of the pressurization will be described with reference to FIG. FIG. 4 is a side view of the fixing device according to the present invention, with a cover (not shown) removed. The fixed shaft 7 is fitted to the insulator 11 at both ends by D-cut, and the insulator 11 is fitted to the pressing plate 12. The pressing plate 12 is attached so as to be rotatable about a caulking shaft 21, and is urged counterclockwise by the force of the pressing spring 13. Here, the force of the pressure spring 13 is applied to the elastic layer 6 of the pressure roller 6.
It goes without saying that the balance is achieved by the repulsive force of b.

Next, details of the vicinity of the diode 8 will be described with reference to FIG. The arm portion 14-a of the leaf spring 14 bends and contacts the fixed shaft 7 with an appropriate contact pressure. The leaf spring 14 is connected to the metal plate 22 via the diode 8, and the metal plate 22 is grounded to the frame 4 by screws 23. Therefore, the core metal potential of the pressure roller 6 can be controlled by the characteristics of the diode.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 6 is a drawing corresponding to FIG. 3 in the first embodiment. In the present embodiment, a neutralizing brush 16 is used as a pressurizing conductive plate. The neutralizing brush 16 is fixed to a fixed shaft 7 by a screw 17, and a brush part 16-a as a contact of the neutralizing brush 16 is pressurized. Core 6-a of roller 6
To form a sliding contact to establish conduction. Here, it goes without saying that the material of the charge removing brush 16 is a conductive material such as stainless steel fiber or carbon fiber.

According to this embodiment, the contact pressure is reduced, and the durability is improved. Other effects are the same as above.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
Will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 7 is a drawing corresponding to FIG. 3 in the first embodiment. In this embodiment, the pressure conducting plate 10 is attached to the core 6-a of the pressure roller 6, and the contact 1
O-a comes into contact with the fixed shaft 7 to form a sliding contact, thereby obtaining conduction. In the present embodiment, the processing of the core metal 6-a of the pressure roller 6 takes more time than in the first embodiment, but the sliding speed of the contact 10-a is reduced, so that the durability is excellent. Other effects are the same.

In the first embodiment, the potential of the metal core of the pressure roller 6 is controlled by using the diode 8, but there are various other control methods such as simply grounding or applying a bias. is there.

Further, in the above-described embodiment, the case where the potential control is performed only on the core metal of the pressure roller has been described. However, a sliding contact is also provided on the heating roller with the same configuration to control the potential of the core metal. Can also.

Further, in the above-described embodiment, an example using a heating roller has been described.
No. 82, JP-A-2-1577878, JP-A-4
As disclosed in JP-A-44075-44083 and the like, a heat source is provided on one side of a heat-resistant film, and a recording material is brought into close contact with the other side to travel and move the recording material together with the film so that the heat energy of the heat source is transferred to the film. Even in a fixing device of a system for applying to a recording material and a toner image on the recording material through the pressure roller having the sliding contact as described above, a heat source disposed inside the film, If it is arranged to be pressed through the film, in the film type fixing device,
The above-described reliable core metal potential control can be performed.

[0044]

As described above, according to the present invention,
The following effects are obtained.

First, according to the first aspect of the present invention,
By rotating the core of the roller body around the central axis via the bearing member, the mounting area of the contact for providing the sliding contact is secured in the gap between the core and the central axis, In addition, the sliding contact is located at the axial center of the bearing ,
That is, the contact area is provided inside the roller body, so that there is no relative movement of the sliding contact even if the center axis or the core metal is displaced, so that the contact area is
The surface can be stably secured, and the contact pressure can be stabilized. As a result, reliable core metal potential control can be performed, and the occurrence of noise at the contact can be prevented. Furthermore, that Do and space can be saved so positioned serves to sliding contact inside the bearing member which has conventionally been a dead space. Also, since the bearing member supporting the roller may be conductive or insulating,
The degree of freedom in design can be improved.

Next, according to the second aspect of the present invention,
Since the core of the roller body is formed in a cylindrical shape, and the core is rotated around the bearing member, it becomes easy to secure the concentricity of the core, and the sliding contact is formed on the inner peripheral surface side of the core. Therefore, even if the central axis or the core metal is displaced, stable core metal potential control is possible. In addition, since the sliding contact is a highly rigid roller core, noise is unlikely to occur. Furthermore, the position of the sliding contact is
A sufficient distance from the conductive member outside the roller body is secured, and no leak occurs.

According to the third aspect of the present invention,
Since the core of the roller body has a cylindrical shape and the sliding contacts are provided on the outer peripheral surface side of the central shaft, not only the same effects as in the second invention are obtained, but also the outer peripheral surface of the central shaft is Since the diameter is smaller than the inner peripheral surface, the sliding speed is reduced, and the wear resistance can be improved.

Further, according to the fourth aspect of the present invention, even when one of the pair of recording material conveyance members is a film-shaped member which is disposed endlessly movable, the sliding contact is in the above-mentioned position. In order to set the roller member, it is possible to arrange the roller body as in the past, so as to be in pressure contact with the heat source disposed inside the film-shaped member via the film-shaped member. In addition, it is possible to realize reliable core metal potential control by stabilizing the contact pressure of the sliding contact.

According to the fifth aspect of the present invention,
Even in a fixing device using a heating roller and a pressure roller,
By providing the sliding contact at the above-mentioned position in the pressure roller, the heating roller and the pressure roller can be brought into pressure contact with each other as before, realizing reliable core metal potential control by stabilizing the contact pressure of the sliding contact. can do.

Further, according to the fifth aspect of the present invention, by providing the sliding contacts on both the heating roller and the pressure roller, it is possible to realize more reliable core metal potential control.

[Brief description of the drawings]

FIG. 1 shows a fixing device according to a first embodiment of the present invention, and is a detailed view of a sliding contact portion having a cross section taken along a line connecting the axes of a heating roller and a pressure roller.

FIG. 2 is a view showing the entire cross-sectional view of FIG. 1;

FIG. 3 is a sectional view taken along line AA of FIG.

FIG. 4 is a side view of the fixing device according to the first embodiment of the present invention, showing a state where a cover is removed.

FIG. 5 is a side view in which a cover is attached to FIG. 4, and is a diagram illustrating a diode attachment portion.

FIG. 6 is a view showing a second embodiment of the present invention and corresponding to FIG. 3 of the first embodiment.

FIG. 7 is a view showing a third embodiment of the present invention and corresponding to FIG. 3 of the first embodiment;

FIG. 8 is a cross-sectional view illustrating an example of a conventional fixing device and corresponding to FIG.

FIG. 9 is a cross-sectional view illustrating an example of a conventional fixing device and corresponding to FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heating roller (recording material conveyance body pair , roller body) 2 Halogen heater (heat source) 6 Pressure roller (recording material conveyance body pair , roller body) 6-a Core 6-b Elastic layer (surface layer) 6-c Surface Layer (surface layer) 7 Fixed shaft (center shaft) 9 Ball bearing (bearing member)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/20 G03G 15/20 G03G 21/00 350-352

Claims (6)

(57) [Claims] 1. A conveyance device for holding a recording material carrying an unfixed image.
Comprising a to that recording material conveying member pair and the recording material conveying member pair heat source disposed on at least one of the, in the fixing device you fixing an unfixed image on a recording material, at least one of the recording material conveying member pairs has a central axis, the <br/> central axis is rotatably supported by bearings in, and a roller body having a metal core and a coating layer provided et the on metal core, the metal core
Sliding on the center side of the bearing that conducts between the
And a conducting member that conducts the center axis outside the bearing.
A fixing device. 2. The fixing device according to claim 1, wherein the core of the roller body has a cylindrical shape, and the sliding contact is provided on an inner peripheral surface side of the core. 3. The fixing device according to claim 1, wherein the core of the roller body has a cylindrical shape, and the sliding contact is provided on the outer peripheral surface side of the center shaft. 4. The recording material transporting body pair includes a roller member on one side and a film-like member on the other endlessly movable, and the roller body is disposed inside the film-like member. The fixing device according to claim 1, wherein the fixing device is disposed so as to be in pressure contact with the heat source via the film-shaped member. 5. A recording material conveying body pair , one of which is a heating roller having a heat source therein, and the other is a pressing roller disposed so as to press against the heating roller, wherein the roller provided with a sliding contact. 4. The fixing device according to claim 1, wherein the body is the pressure roller. 6. A recording material conveying member pair includes a heating roller having a heat source therein, and a pressure roller disposed so as to be in pressure contact with the heating roller. The fixing device according to any one of claims 1 to 3, wherein the fixing device is a provided roller body.